The INA500 is an integrated difference amplifier that processes large differential voltages while simultaneously rejecting larger common-mode voltages. The device offers a low power consumption of 13.5µA (typical) and has a smaller form factor.

With the specifications above, the device is a good fit for portable applications that are powered with single cell or coin-cell batteries. Often, these systems do not need sophisticated battery management technology but a solution that is rather simple and small-size. In a few other systems, battery monitoring ICs are preferred to perform sophisticated functions including cell balancing, protection, voltage and current sensing and so forth but these systems still need a secondary level of protection or redundancy with a simpler and reliable solution for system integrity. It is in these scenarios, the amplifier based battery monitoring application shown below could be quite useful.

Figure 8-2 shows an example circuit that monitors a 12V battery voltage and interfaces it to an ADC that is powered using a 3V power supply. The main advantage for using difference amplifiers in this application is the elimination of ground bounce, which is a common-mode signal, when measuring the battery voltage. These ground bounce signals, when not rejected, are capable of causing errors in the range of few milli-volts to tens or hundreds of milli-volts.

Figure 8-2 Battery Monitoring Circuitry